What’s causing the rising number of epidemics under the sea?

While above ground the world grappled with a pandemic, a problem has been swimming below the surface

Black sea urchin under the sea
Sea urchins have been devastated by a mysterious disease
(Image credit: AlexeyMasliy via Getty Images)

A mysterious disease is spreading among marine mammals, leading experts to worry about the future of creatures living underwater.

Mass mortality of aquatic life is presenting a conundrum for scientists, who are now in a race against time to discover what is killing off swathes of pelagic animals.

How did the deaths start?

It is a “deadly epidemic” in the Red Sea that has sparked cause for concern, said Reuters, as an unknown illness has “killed off an entire species of sea urchin in the Gulf of Aqaba”.

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These black creatures are well known for “helping keep coral reefs healthy”, the news site added, but were “wiped out over a couple of months”.

Researchers from Tel Aviv University, Israel, have warned the situation appears so dire that “only skeletons” now remain at the site they have investigated, reported science website Phys.org.

Similar phenomena have been reported “in other countries in the region, including Jordan, Egypt, Saudi Arabia, Greece, and Turkey”, adding to fears about what this could mean for life under the sea.

Is it a new phenomenon?

The notion that both sea creatures and coral reefs are under threat is sadly not a new issue. In fact, between 1955 and 2018, a “sixth of marine mammal species have suffered a mass die-off caused by an infectious disease”, wrote Bradley van Paridon for Hakai Magazine in 2020. Van Paridon warned the Covid-19 pandemic reminds us of the “devastation disease outbreaks can cause”, but stressed these “do not only affect humans”.

As for the reason behind mass mortality rates below the surface of the water, “no one is sure”, The Washington Post added. However, in the Pacific Coast, a similar problem has been faced, “causing starfish to literally melt into goo”.

The newspaper suggested the disease is so prolific and ravaging that it can cause death among creatures “within hours of showing symptoms”. Reuters added that while some sea urchins wash up dead, others are “eaten by fish, likely speeding up contagion”.

What do scientists think is happening?

The Guardian cited findings which suggested “matter in melting ice” could be behind the disease, because rising temperatures due to climate change make it “more likely that viruses and bacteria locked up in glaciers and permafrost could reawaken and infect local wildlife”.

The newspaper warned of the risk of “viral spillover – where a virus infects a new host for the first time”, and its potential frequency “close to melting glaciers”.

AP News said that for now, “localised poisoning or pollution” has been ruled out as a cause of the disease, but scientists are now focusing their attention on “a single-celled parasite” which has “laid waste” to underwater ecosystems. Focusing on a similar issue discovered in the Caribbean, New Scientist says the culprit here is a microorganism with “tiny hair-like structures over its body”.

What can be done to stop the epidemic from spreading?

“Nothing…at the moment”, lead researcher Omri Bronstein, told Reuters. “We need sea urchins. Without this species, as we’ve seen – this is not imagination, we’ve seen it happening in front of our eyes – it is not a good future.”

In the meantime, researchers and politicians are looking for ways to protect the human population from the spread of disease, learning lessons from the Covid-19 pandemic, and observing the phenomena occurring underwater.

George Freeman, the science minister, told The Telegraph the government is considering installing “advanced sensors” in shipping ports, in the hopes of detecting and tracking the spread of infectious disease.

Identifying pathogens, said the newspaper, would “allow governments to take immediate action against emerging diseases of concern before they escalate into major outbreaks”, but the strategy remains in its infancy, Freeman added.

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Rebekah Evans joined The Week as newsletter editor in 2023 and has written on subjects ranging from Ukraine and Afghanistan to fast fashion and "brotox". She started her career at Reach plc, where she cut her teeth on news, before pivoting into personal finance at the height of the pandemic and cost-of-living crisis. Social affairs is another of her passions, and she has interviewed people from across the world and from all walks of life. Rebekah completed an NCTJ with the Press Association and has written for publications including The Guardian, The Week magazine, the Press Association and local newspapers.